Punjab was a province of British India, it was one of the last areas of the Indian subcontinent to fall under British rule. With the end of British rule in 1947 the province was split between India and Pakistan. The area that made up British Punjab streched from Himachal Pradesh in the east to Khyber Pakhtunkhwa in the west, which itself was separated in 1909; has today been split into the following areas:

In 1947, the province of Punjab was divided between the new republics of India and Pakistan. The mostly Muslim western part of the province became Pakistan's Punjab Province; the mostly Sikh and Hindu eastern part became India's Punjab state in 1966. Many Hindus and Sikhs lived in the west, and many Muslims lived in the east, and so the partition saw many people displaced and much intercommunal violence. Lahore and Amritsar were at the center of the problem, the British were not sure where to place them - make them part of India or Pakistan. The British decided to hand both cities to India, but because of a lack of control and regulation for the border, Amritsar became part of India while Lahore became part of Pakistan. Areas in west Punjab such as Lahore, Rawalpindi, Multan, Gujrat, had a large Sikh population and many of the residents were attacked or killed by radical Muslims. On the other side in East Punjab cities such as Amritsar, Ludhiana, and Gurdaspur had a majority Muslim population in which many of them were wiped out by Sikh guerrillas who launched an all out war against the Muslims.